Method of manufacturing lawn-tennis and like balls.



J. TURNER & A. -BUXTON.

METHOD OF MANUPAOTUBIN wn TENNIS n m: BALLS;

' APPFIOJH'IOI 1 D MAY 23, 19

atented Feb. 13, 1912.

Fig.1:

nv VENTO R5, $44M, M

WITNESSES.

UNITED STATES PATENT OFFICE.

JOHN TURNER AND ANTHONY BUXTON, OF UXBRIDG-E, ENGLAND, ASSIGNORS TO THE RUBBER PATENTS LIMITED, OF COWLEY, ENGLAND, A CORPORATION OF GREAT BRITAIN.

METHOD OF MANUFACTURING LAWN-TENNIS AND LIKE BALLS.

Specification of Letters Patent.

Patented Feb. 13, 1912.

Application filed May 23, 1910. Serial No. 562,904.

Tennis and Like Balls, of which the fol-'- lowing is a specification.

This invention relates to an improved method of manufacturing lawn tennis and like balls, the object being to produce a ball which has an even wall without seams or heavy protuberanccs or masses inside of same which act to prevent an even bounce or to destroy its balance in flight or play, and which has better air holding qualities than the usual ball.

The invention will be described in connection with the accompanying drawings which show typical examples of certain parts hereinafter referred to and views of a ball and its parts in difierent stages, Figure 1 being a sectional elevation of a plunger, Fig. 2 a similar view of a lower mold, Fig. 3 a similar view of an upper mold. Fig. 4 is a View of an internal supporting ball or bladder, and Fig. 5 a section of one form of completed ball. Fig. 6 is a section of a part of a modified form of ball.

According to the invention shown in Figs. 1 to 5, the main portion of the ball formed of two died out half spheres a; or several died out segments or parts of cured or vulcanized rubber or rubber compound, the quality of which varies according to the class of ball to be made, and which are connected together by a gutta percha or gutta percha compound solution or other suitable adhesive under heat and external pressure, the interior of the seam being preferably supported by pressure also which may be done by a thin rubber ball or bladder 12 holdin air under pressure.

In orming a ball such as described a half or suitable mold c is employed in which is placed uncured rubber or a compound of rubber in a. plastic state. Into the mold ,is forced a die plun er or chill 0! corresponding in shape an carrying a shoulder or part e adapted to seat in a recess 1 of the mold 0, br being so related thereto that a suitable space is left between the internal face of the mold and the external face of the plunger of the thickness of wall required for the ball a half sphere of which is shown at a Fig. 2 in the mold as having been just formed. The half sphere a or segment so formed is then cured or semicured by heat applied externally of the mold and plunger while still held between said mold and plunger so that shrinkage is avoided. When removed the edges g of two half spheres or the edges of the various segments are treated with a solution of gutta' percha or gutta. percha compound or other suitable adhesive which will not cure with the fumes of the sulfur or heat and will hold the edges firmly. If no inner ball or bladder is to be used the two half spheres or segments are then transferred to molds somewhat smaller than those they have been made in, so thatincreased pressure is exerted on them to secure them together, the process being the same as that where a bladder is emp yed as hereinafter described, except that 1n place of the support of the inner bladder the usual carbonate of ammonia, or the like may be used to hold inflating and closing which projects outside of same. Such plug is of gutta. percha or gutta percha compound as that not affected by the sulfur fumes of the cured parts or is of some suitable material which will not cure and will close any hole made in it tightly as the instrument is withdrawn under heatand pressure. The inner ball or bladder is then blown (by the usual air needle piercing the plug) up to about the dimensions of the inside of the half spheres or segments, for which purpose the plug it is heated and when the needle is withdrawn is compressed and the ball or bladder is placed inside one half sphere a, the other half a which corresponds internally with the first half a being then fitted over it. The

, placed between the half s heres or the segplug h when the inner ball or bladder is mcnts, comes between the inner ball or bladder and such half spheres or segments and is pressed against the inside of one of the latter; The slight pressure developed by the closing of the two halves causes the solutioned edges g to adhere sutliciently firmly for the ball to be placed in molds somewhat smaller than those it has been made in but of the same character if desired so that a considerable pressure is exerted on it and in these molds it is heated up to about vulcanizing heat though for such a Short period that the curing of the parts is not repeated if the ball is already cured or if it is semicured it is heated until fully so,- the duration of heatingbeing only sufficient to soften the gutta percha solution and cause it. to adhere firmly. During this heating the outer pressure of the molds is counteracted by the expansion by heat of the inner ball, the outer wall being thus supported all over the seam or seams as well as over its general surface both inside and outside of same. Thus it will be seen that the ball or bladder 7) acts for supporting the wall and joints or seams and not for getting the shape as that is obtained in the first instance by the plunger. The ball is now removed from the molds and pierced by passing an air needle through 'the outer casing a and plug h of the inner ball or bladder b and is inflated to the pressure and dimensions desired. The plug it is-warmed throu h the outer cover in some suitable way be ore'piercingas by holding the face of the'ball to a source of heat and is afterward pressed from the outside when the needle is removed. The result of the heating and compression is that the plug 1) is softened and spread as represented at h Fig. 5, so that it forms only a comparatively slight thickening of the wall of the ball at this point although it is sufli: ciently retained to act as a closure for the air needle opening when withdrawn, while it further acts to close the puncture formed by the needle in the outer casing by slightly protrudin when Warm into the opening left by sue needle and setting hard therein.

Where it is not desired to employ the internal support or pressure the internal ball or bladder may be omitted as shown in Fig. 6, and in this case a plug of gutta percha or like material j which will not cure as described, is attached to the inside of the walls i of the ball to provide a closure for the needle.

In the claims it is tobe understood that the expression rubber includes any suitable rubber compound.

What we claim is 1. Themethod of manufacturing lawn a plastic state, then curing sauie while still held between the members of the die, and then cementing the cured parts together by an adhesive which will not. cure by the fumes from the cured parts.

2. The method of manufacturing lawn tennis or like balls which consists in dying out parts of same from uncured rubber in a plastic state, then curing same while still held between the members of the die, and then cementing the cured parts together by an adhesive which will not cure by the fumes from the cured parts and under heat and pressure. i

3. The method of manufacturing lawn tennis or like balls-which consists in dying out parts of same from uncured rubber in a plastic state, then curing same while still held between the members of the die. then cementing the cured parts together by an adhesive which will not cure by the fumes from the cured parts and under heat and pressure and then transferring the ball to the members of a mold capable of exerting increased pressure and heating such mold members for a short period.

4. The method of manufacturing lawn tennis and like balls which consists in dying out parts of same from uncured rubber then curing saute while still held between the members of the die, then applying to the edges of the cured parts an adhesive which will not cure by the fumes from the cured parts, then inserting inside the parts an internal 'bladder and then transferring the ball to the members of a mold capable of exerting increased pressure and heating such mold members for a short period.

5. The method of manufacturing lawn tennis and like balls which consists in dying out parts of same from uncured rubber then curing same while still held between the members of the die, then applying to the edges of the cured parts an adhesive which will not cure by the fumes from the cured parts, then inserting inside the parts an internal bladder carrying a plug of material which will not cure and any opening made in which will readily close and then transferring the ball to the members of a mold capable of exerting increased pressure and heating such mold members for a short period.

'In testimony whereof we have hereunto set our hands in the presence .of two sub scribing witnesses.

JOHN TURNER. ANTHQNY BUXTON. Vitnesses I'IERBERT C. Bnoomrmm, FRANCIS TV. KING. 

